The present disclosure relates to a piston cooling jets, and more particularly to selectively tunable (e.g., spray direction and patterns) oil jets for cooling engine pistons.
There are continuing efforts to develop new and improved ways in which to cool engine pistons and cylinders. As engines become more efficient, run at higher compression ratios and cylinder pressures (e.g., turbocharging and supercharging) and emitting lower emissions, the engines, and in particular the pistons and cylinders run hotter, e.g., at higher temperatures. Increased thermal loading of pistons can, however, cause problems such as, engine degradation and seizures.
While it is desirable to effectively and efficiently cool and/or lubricate the pistons and cylinders, incorporating systems to avoid such degradation can involve higher-cost materials and manufacturing methods. One known system, a piston and cylinder oil squirter system, uses one or more squirter rails having an inlet connected to an oil source and one or more outlets connected to at least one oil supply rail. The oil supply rail includes a manifold with integral oil squirter nozzles and attachment brackets. An oil flow control valve placed before the oil supply manifold controls oil flow to the oil rails and nozzles in response to engine requirements. One drawback to such a system is that the oil is squirted (supplied) to the piston and cylinder on a constant basis, regardless of the position of the piston in the cylinder.
In another system an oil supply is repeatedly activated only during a part of a cylinder cycle synchronous with a frequency of piston reciprocating motion. In this way, oil supply may be provided during a portion of the engine cycle and not in a continuous manner. Such a system resolves the issue of a proportion of the oil supply being sprayed without cooling the piston due to the reciprocating motion of the piston. However, the system uses a series of poppet valves to control the flow of oil to each piston in which a piston skirt contacts the poppet valve to open the valve. While such a system functions to supply or spray oil at a desired location and time in the engine cycle, there is nevertheless contact between the piston skirt and poppet valve.
Still other systems show that a cooling and lubricating jet of oil can be supplied to individual piston/cylinder combinations using, for example, the position of the crankshaft to control the flowrate and timing of oil flow to the piston, and an oil flow controller than controls the flowrate of oil to the piston in response to engine temperature.
While all of the above-noted systems function to supply oil to the piston to effect piston cooling they all require fairly complex system to carry out timing and/or actuation of the oil spray to effect piston cooling.
Accordingly, there is a need for a system that is a drop-in rail or manifold system that includes a rail or manifold with a series of individual cooling jets or nozzles that can be directed at specific desired locations of the piston, for example at an area of the piston near the exhaust port or valve. Desirably, such a system includes a control device, such as a solenoid valve, check valve, thermostatic valve or the like to control the flow of oil to the cooling jets.
More desirably, in such a system, the manifold is not tied to any other critical galleries of the engine and can be shut off without isolating the oil supply to any other parts of the engine.